In a 2006 Honda Civic, the backup fuse does not directly connect to the Mass Air Flow (MAF) sensor. The MAF sensor is primarily responsible for measuring the amount of air entering the engine to ensure the correct air-to-fuel ratio for efficient combustion. However, in rare cases, a blown backup fuse can indirectly affect the MAF sensor.

The backup fuse, often labeled as "Backup" or "Back-Up," is typically connected to various systems and components related to the vehicle's electrical power supply, such as the audio system, interior lights, and sometimes the ECM (Engine Control Module). The ECM is the main computer that controls the engine's operations, including managing the MAF sensor readings.

If the backup fuse blows, it may result in the loss of power to multiple systems, potentially including the ECM. In this scenario, the MAF sensor may not receive power or may not communicate properly with the ECM. Consequently, the engine performance may be affected, including issues like rough idle, hesitation, reduced power, or even stalling.

In case you suspect a fault in the MAF sensor, it is essential to check all relevant fuses, including the backup fuse, to ensure they are not blown. However, if you are experiencing specific issues related to the MAF sensor or engine performance, it is recommended to have the vehicle diagnosed by a professional mechanic. They can use specialized tools to assess the MAF sensor, ECM, and related components accurately and provide a precise diagnosis and repair solution for your 2006 Honda Civic.